T.U.F.F. Puppy is an American animated television series created by Butch Hartman. It debuted on October 2, 2010 on Nickelodeon after the premiere of Planet Sheen. T.U.F.F. Puppy aired on Nickelodeon Canada on January 7, 2011. The show's main character is a dog named Dudley Puppy (voiced by iCarly 's Jerry Trainor), who works as a secret agent for an organization called T.U.F.F. (Turbo Undercover Fighting Force). His partner is a cat named Kitty Katswell (voiced by Grey DeLisle). The show takes place in a fictional city called Petropolis, which is populated by animal characters.

Protagonists

Dudley Puppy (Jerry Trainor) - The dimwitted and hyperactive white mixed-breed dog who wears nothing more than a black shirt and has a habit of chewing on his butt. Keswick's DNA analyzation shows that Dudley is the "perfect mix of every breed of dog known to man". He inherited the signature traits of each dog breed, such as a Bloodhound's sensitive nose, Greyhound's speed, German Shepherd's bravery and a "splash" of Billy Goat which cannot be explained, even by Keswick.

Kitty Katswell (voiced by Grey DeLisle) - is T.U.F.F.'s number one agent as well as Dudley's partner and best friend. Skilled in various fighting styles and use of firearms, short tempered, and easily startled, this feline is a force to be reckoned with.

Keswick (voiced by Jeff Bennett), works for the T.U.F.F headquarters as their primary inventor and scientist although whatever he invents is usually worthless due to the fact that it shoots acid or is too dangerous. Usually, when he speaks, he stutters and is similar to Jerry Lewis' on-screen persona as portrayed in The Nutty Professor. A running gag is that no one knows Keswick's species. It's shown that he has a pouch, gills, webbed feet, looks like a labradoodle and can lay an egg.

The Chief (voiced by Daran Norris) - A tough but good-natured flea who runs T.U.F.F. headquarters. In "Internal Affairs", it's revealed that his real name is Herbert Dumbrowski, he has a bionic foot, and has short term memory loss.

Other T.U.F.F. agents

Agent Nutz (also voiced by Jeff Bennett) - An agent who is a squirrel. He mostly says "stop following me".

Agent Jumbo - An agent who is an elephant. She has a tendency to freak out whenever she sees a mouse, especially when Agent Rodentski appears.

Agent Rodentski - mouse agent, in one episode used as camouflage by the Chameleon.

Antagonists

Verminious Snaptrap (voiced by Matthew W. Taylor) – An evil and stupid rat and the leader of the Diabolical Order of Mayhem. Despite being a rat, he is allergic to cheese which causes him to swell up.

The Chameleon (voiced by Daran Norris) - An evil and stupid chameleon who wants to get revenge on Kitty for putting him in jail (reasons unknown). He attempts to destroy T.U.F.F., but never succeeds. He can disguise himself as any person or object using his transformation suit.

Bird Brain (voiced by Rob Paulsen) – An evil blue-bottomed booby genius who can't fly with his wings (something he always forgets). Despite his species name's origin which is from the Spanish word "bobo" or "stupid", he is Petropolis' most competent villain.

Snaptrap's Henchmen or D.O.O.M.

Larry (voiced by Jeff Bennett) – A shrew that is Verminious Snaptrap's brother-in-law (Larry's married to Snaptrap's sister) and one of his three main henchmen. Despite being considered dim-witted by Snaptrap, Larry is the second smartest and most intelligent of his three main henchmen.

Ollie (voiced by Jeff Bennett) – A sensible and smart British opossum who is one of Snaptrap's main henchmen. Ollie is Snaptrap's voice of reason whom he often ignores.

Francisco (voiced by Daran Norris) – An alligator who is one of Snaptrap's three main henchmen. He is also the only one of Snaptrap's henchman who seems to take villainy seriously. In "Dog Dish", he kept trying to convince Snaptrap to use the invisibility helmet for more evil deeds than sneaking into the movies.

Bad Dog (voiced by Jeff Bennett in the first appearance, Daran Norris in later appearances) – A pit bull and one of Snaptrap's henchmen. He is often seen with a black torn sleeveless shirt with a skull on it (similar to The Punisher's T-shirt). Bad Dog is often paired up with Leather Teddy. He stops appearing after the first season.

Leather Teddy (voiced by Eric Bauza) – A leather clad blue bear and one of Snaptrap's henchmen that wears an eyepatch (though the first episode shows that he still has an eye under the eyepatch). He wields bear traps on chains for weapons. Leather Teddy's outfit gives him the appearance of a biker. He is often paired up with Bad Dog. He stops appearing after the first season.

The Mole (voiced by Matthew W. Taylor) – A mole agent who is Snaptrap's master of infiltration. He stops appearing after the first season.

The series finally got its own DVD release in the form of the T.U.F.F. Puppy: Season One manufacture-on-demand DVD set on June 23, 2014. It was followed up by Season Two on January 8, 2015. To date, there is still no DVD set of the third season.